Spring Data Redis Messaging – PubSub example | Spring Boot

https://grokonez.com/spring-framework/spring-boot/spring-data-redis-messaging-pubsub-spring-boot-spring-data-redis-example

Spring Data Redis Messaging – PubSub example | Spring Boot

The previous post introduces way to do Redis CRUD Operations. In this tutorial, we're gonna look at how to implement Redis Messaging- PubSub with Spring Boot.

Related Post: Spring Data Redis CRUD Operations example with Spring Boot

I. Technology

• Java 1.8
• Maven 3.3.9
• Spring Tool Suite – Version 3.9.0.RELEASE

• Spring Boot: 1.5.9.RELEASE

  II. Spring Data Redis Messaging - PubSub

  1. Overview

  Spring Data provides dedicated messaging integration for Redis that can be roughly divided into two areas of functionality: production (or publication) and consumption (or subscription) of messages.

• Publisher doesn't know specific subscribers to send messages to. Instead, Publisher specifies channel.

• Subscriber receives messages from one or more topics, without knowledge of Publisher.

  2. Maven Dependency

  <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-redis</artifactId>
  </dependency>

  3. Redis Configuration

  We need:

• connection factory -> JedisConnectionFactory

• a channel -> ChannelTopic

• a template for publisher to publish messages -> RedisTemplate

• a message listener for consumer to consume messages -> RedisMessageListenerContainer
  

  @Bean
  
  JedisConnectionFactory jedisConnectionFactory() {
  
  return new JedisConnectionFactory();
  
  }

@Bean
public RedisTemplate<String, Object> redisTemplate() {
final RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();
template.setConnectionFactory(jedisConnectionFactory());
template.setValueSerializer(new GenericToStringSerializer<Object>(Object.class));
return template;
}

@Bean
MessageListenerAdapter messageListener() {
return new MessageListenerAdapter(new CustomerInfoSubscriber());
}

@Bean
RedisMessageListenerContainer redisContainer() {
final RedisMessageListenerContainer container = new RedisMessageListenerContainer();
container.setConnectionFactory(jedisConnectionFactory());
container.addMessageListener(messageListener(), topic());
container.setTaskExecutor(Executors.newFixedThreadPool(4));
return container;
}

@Bean
CustomerInfoPublisher redisPublisher() {
return new RedisCustomerInfoPublisher(redisTemplate(), topic());
}

@Bean
ChannelTopic topic() {
return new ChannelTopic("pubsub:jsa-channel");
}
We can also supply an executor within RedisMessageListenerContainer for asynch manner of messages.

https://grokonez.com/spring-framework/spring-boot/spring-data-redis-messaging-pubsub-spring-boot-spring-data-redis-example

Spring Data Redis Messaging – PubSub example | Spring Boot